Photographic film with laminated support having increased flexibility



may 2m, w24. :#194479 .15. H. HASTE PHOTOGRAPHIC FILM WITH LAMINATED SUPPORT HAVING INCREASED FLEXIBILITY Filed Dec. 26. 1922 ce e miraie.

ENVEN'OR ATF@ NEY Patented May 20, 1924.

STATES PATENT OFFICE.

JAMES H. HASTE, OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COLM- PANY, OF ROCHESTER, NEW YORK, A CORPORATION F NEW YORK.

PHOTOGRAPHIC FILM WITH LAMINATED SUPPORT HAVING INCREASED FLEXIBILITY.

Application led December 26, 1922. Serial No. 609,123.

To aZ 'fw/20m 2'15 lmay concern.'

Be it known that I, JAMES H. HAsTE, a citizen of the United States of America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Photographic Films vwith Laminated Supports Having Increased Flexibility, of which the following is a full, clear, and exact specification.

This invention relates to photographic film, the support of which is laminated. One object of the invention is to provide a film, theflexibility of which will be increased both. in degree and permanence withoutimpairing other desirable qualities. Other objects will hereinafter appear.

The single figure in the drawing shows a diagrammatic sectional view of one embodiment of my invention on an exaggerated scale.

When attempts are made to increase the flexibility of photographic films by increasing the amounts of customary flexibility-inducing substances in the compositions of the support, limits are quickly reached because other qualities, such asstrength, hardness, transparency and the like may be impaired before the desired degree of flexibility is obtained. It has now been found that when the support is composed of compositions based chiefly upon cellulosic addition compounds, such as cellulose acetate, cellulose ether and nitrocellulose, the flexibility is affected to an unusual degree by very small amounts of moisture regardless of other flexibility-inducing substances. Quantities of moisture, which are not detectable by touch but only by careful analytical methods greatly alter the suppleness and flexibility of the film.

. I have discovered that the benefits due to small amounts of moisture may be obtained in a very durable form by creating a localized reservoir of moisture within the film,

rather than by initially distributing the entire reserve of moisture throughout the body of the film. In other words, I find that the flexibility of the film may be increased by providing a laminated support, the layers of which are interunited in a zone which contains a reserve of moisture.`

In the drawing, l indicates any suitable photographically sensitive layer, say, for in- 95 stance, a coating of gelatino-silver haloid emulsion. Layers 2, which constitute the support, are composed of addition compounds such as cellulose acetate, cellulose ether, and nitrocellulose. Since cellulose acetate gives the most marked results when the reservoir of moisture-carrying material of my invention is employed, I use it in the preferred form of my invention, but the principle is very useful also in connection with laminated celluose ether and nitrocellulose films. At 3 I have indicated the zone of interunion in which 'the entire adjacent faces of the laminationsfare blended or welded together by a cement. Because of. the lack of a sharp line of demarcation, solid lines have been omitted from the boundaries of this layer 3.

The compositions of the layers 2 may be those usually employed for the manufacture of flexible films. These layers, say of cellulose acetate, are welded or cemented by hand or by any usual apparatus for uniting sheet materials of this kind. The followin cement illustrates one that is suitable for orming my moisture reservoir,-2J parts of glycerin mixedwith a bath of 20 parts acetone, 20 parts methyl alcohol, 40 parts methyl acetate, 19 parts but l acetate, and a trace of cellulosic materia addition compound, say, for instance, 1 part of nitrocellulose. The B0 glycerin preferably has moisture absorbed in it before it is mixed in the cement but it may absorb the moisture later.

The zone or layer of interunion 3, thus produced, contains the moisture-carrying substance of the cement, of which gycerin is the preferred example, and thereby possesses a reserve of moisture. If the layers 2 tend to become too dry, especially in an arid climate, the moisture from this reserve works its way out from zone 3 into said layers and maintains their flexibility to a degree that is strikingly useful. The above formula is also applicable to nitrocellulose films. When cellulose ethers are employed, it may be ma modified by using other solvents, such as ethyl alcohol or chloroform in place of methyl acohol and acetone.

Having thus describedmy invention, what I claim as new and desire to secure by Let- 105 ters Patent is:

1. As an article of manufacture, a photographic film com rising a photographically sensitive layer an a laminated flexible lighttransmitting support therefor, Said support o including a plurality of layers of cellulosic addition compounds, the flexibility of which compounds is enhanced by moisture, said layers being interunited throu hout their adjacent faces and each zone 0i; interunion containingr moisture-carrying material. l

Q. As :in article of manufacture, a photographic film comprising` a photographically7 sensitive layer and :1 laminated flexible transparent support therefor, including two layers of cellulose acetate united by a composition containing a hygroscopic substance to increase the flexibility of said support.

3. As an article of manufacture, a photographic film comprising a photographically sensitive layer and a sup rt therefor, including two layers of cellu ose acetate united by a composition containing cerin.

Signed at Rochester, New Ygdyrk, this 16th day of December, 1922.

JAMES H. HASTE. 

